: This proposal is based on exciting preliminary findings that show attenuation of baroreceptor function in rodents exposed to intermittent hypoxia (IH) during the 1st month of life. IH has been previously shown to induce hypertension similar to that found in sleep-disordered breathing. We hypothesized that the occurrence of IH during a critical period of development would lead to long-lasting alterations in baroreceptor properties that could predispose for the development of hypertension in susceptible individuals. We therefore propose to determine whether (1) lH during prenatal life modifies baroreceptor sensitivity during adulthood; (2) lH during early postnatal life modifies baroreflex sensitivity during adulthood; and (3) lH during early postnatal life leads to accelerated development of systemic hypertension in spontaneously hypertensive rats. These studies have the potential to uncover important mechanisms underlying the emergence of systemic hypertension in genetically susceptible subjects, and will further demonstrate the importance of early developmental antecedents in disease causation.